Neocercosporella Sanjay Yadav & Raghv. Singh, in Yadav, Singh, Verma, Singh & Kushwaha, Mycol. Progr. 22(4, no. 26): 10 (2023)

Index Fungorum Number: IF 840500, MycoBank Number: MB 840500, Facesoffungi Number: FoF 15860

Etymology – derived from the genus name Cercosporella.

Diagnosis – differs from Cercosporella s. str. by its conidiogenous locus, which is conical in shape and has a small, rim-like depression on the top, encircling a small, fat, protuberant-like structure. In Cercosporella, conidiogenous cells are terminal and conidia formed singly, while conidiogenous cells in Neocercosporella are terminal and intercalary, and the conidia are produced at least initially in chains. It also difers from Acervuloseptoria due to its hyphomycetous nature, while the latter is coelomycetous.

Description – Plant pathogenic, foliicolous. Hyphae restricted to intercellular spaces. Colonies hypogenous. Stromata substomatal or subcuticular to erumpent. Conidiophores macronematous, fasciculate, arising from stromata, initially erumping through stomata, later by rupturing epidermis, erect to procumbent, hyaline to light olivaceous, smooth, thin- to thick-walled, unbranched, rarely branched, straight to slightly curved, geniculate at the tip, septate. Conidiogenous cells integrated, terminal and intercalary, polyblastic, sympodial, conidiogenous loci slightly protuberant, thickened and darkened, loci conical having a very small rim-like depression on the top encircling a small fat protuberant-like structure (ultrastructure). Conidia formed singly, rarely catenate, mostly hyaline, rarely light olivaceous, dry, obclavate to obclavate-cylindrical, straight to curved, smooth, thin-walled, euseptate, base obconically truncate to rounded, tip obtuse, hila unthickened, sometimes slightly thickened and darkened.

Type species – Neocercosporella peristrophes (Syd.) Sanjay & Raghv. Singh (≡ Cercosporella peristrophes Syd.)

Notes – Based on a megablast search of NCBI’s GenBank nucleotide database, the closest hits using the ITS sequence had highest similarity to Acervuloseptoria ziziphicola [strain CBS 138009, GenBank NR_156287; identities=461/484 (95%), 8 gaps (1%)], Cercosporella dolichandrae [strain CBS 138101, GenBank NR_156282; identities=459/495 (93%), 11 gaps (2%)] and Cercosporella virgaureae [strain CBS 113304, GenBank GU214658; identities=461/484 (95%), 8 gaps (1%)]. Closest hits using the LSU sequence are Cercosporella virgaureae [strain CBS 113304, GenBank GU214658; identities = 1096/1133 (97%), 6 gap (0%)], Septoria obesa [strain CBS 354.58, GenBank GU214493; identities = 1095/1133 (97%), 6 gap (0%)] and Septoria dysentericae [strain CBS 12328, GenBank GU214699; identities=1092/1133 (96%), 6 gap (0%)]. Closest hits using the RPB2 sequence had highest similarity to Acervuloseptoria ziziphicola [strain CBS 138009, GenBank MF951425; identities=815/891 (91%), 0 gaps (0%)], Cercosporella virgaureae [strain CBS 113304, GenBank KX348051; identities=746/893 (84%), 2 gaps (0%)] and Cercosporella catenulata [strain CBS 355.73, GenBank KX288424; identities=655/795 (82%), 4 gaps (0%)].

Figure 1 – Phylogenetic tree resulting from a RAxML analysis of the combined LSU/RPB2/ITS sequence alignment (dataset 2). The Bayesian posterior probabilities (≥0.90; BI-PP), maximum likelihood bootstrap support values (≥50%; ML-BS) and maximum parsimony bootstrap support values (≥50%; MP-BS) are given at the nodes (BI-PP/ML-BS/MP-BS). The newly introduced lineage is represented in bold and novel genera denoted in blue. The family name Mycosphaerellaceae is unabbreviated, while others are abbreviated as follows: D=Dissoconiaceae, P=Phaeothecoidiellaceae, S=Schizothyriaceae, T=Teratosphaeriaceae, C=Cladosporiaceae. The tree is rooted to Cylindroseptoria ceratoniae (CBS 477.69).